Impact modulator having cascaded control nozzles

ABSTRACT

THIS DISCLOSURE INCLUDES AN IMPACT MODULATOR HAVING OPPOSING MAIN STREAMS WITH A SELECTED OUTPUT IN THE ABSENCE OF ANY CONTROL SIGNALS. TWO PAIRS OF CASCADED CONTROL NOZZLES ARE MOUNTED TO OPPOSITE SIDES OF THE MAIN STREAM AND EACH ESTABLISH A PRIMARY CONTROL SIGNAL STREAM WHICH ENGAGES SAID MAIN STREAM WITH A PERPENDICULAR CONTROL COMPONENT. THE NOZZLES ARE ORIENTED TO ESTABLISH A MOMENTUM VECTOR IN THE CONTROL STREAM WHICH OPPOSES THE STREAM ENGAGED. THE DEVICE CAN BE EMPLOYED TO ESTABLISH POSITIVE GAIN, NEGATIVE GAIN AND LOGIC FUNCTIONS.

Oct. 26, 1971 L. o. ATKINSON mm 3, 1

I IMPACT MODULATOR HAVING CASCADED CONTROL NOZZLES Filed March 3, 1969 2 Sheets-Shoot 1 INVENTORS LOUIS D. ATKINSON OTTO R MUNCH Attorneys Oct. 26, 1971 ATKINSON 3,614,962

IMPACT MODULATOR HAVING CASCADED CONTROL NOZZLES Filed March 5, 1969 2 Sheets-Sheet :3

FIG-6 FIG 5 INVENTORS LOUIS D. ATKINSON BY OTTO R. MUNCH /Z-J@%4 Z Attorneys United States Patent 3,614,962 IMPACT MODULATOR HAVING CASCADED CONTROL NOZZLES Louis D. Atkinson, New Berlin, and Otto R. Munch, West Allis, Wis, assignors to Johnson Service Company,

Milwaukee, Wis.

Filed Mar. 3, 1969, Ser. No. 803,588 Int. Cl. FlSc 1/20 US. Cl. 137--81.5 16 Claims ABSTRACT OF THE DISCLOSURE This disclosure includes an impact modulator having opposing main streams with a selected output in the absence of any control signals. Two pairs of cascaded control nozzles are mounted to opposite sides of the main stream and each establish a primary control signal stream which engages said main stream with a perpendicular control component. The nozzles are oriented to establish a momentum vector in the control stream which opposes the stream engaged. The device can be employed to establish positive gain, negative gain and logic functions.

This invention relates to a multiple purpose fluidic device and particularly to a fluidic device which can selectively perform as a fluidic amplifier and/ or a fluidic logic device.

Recently, fluid control systems have been produced in which a fluid signal stream is employed to control another fluid stream for purposes of amplification, switching and other similar functions which have heretofore generally been based on electronic controls. Pure fluid or fluidic devices have many advantages from the standpoint of reliability and functioning in environments such as electromagnetic fields, radiation fields and the like wherein electrical systems require special protective systems. Fluidic systems have presented other design problems, however, because generally each device is constructed to perform a very limited and particular function. As a result, a substantial number of components with a separate device employed for each stage of the control system and with the required fluid passage interconnection is required for any given installation.

Various pure fluid devices have been suggested for amplifying flow and/or pressures. The various forms of active elements have employed pure deflection control, wall attachment and boundary layer control, vortex control and the like.

An unusually satisfactory fluid amplifier and/or switching device is disclosed in the Bjornsen et a1. Pat. 3,272,215 wherein the output is controlled by the relative strength of a pair of opposed impacting jet streams. The impact modulator is constructed with an independent nozzle and a dependent nozzle mounted in spaced predetermined aligned relationship with an output orifice means preferably provided immediately adjacent the dependent nozzle. The independent nozzle strength is controlled either directly or through a transverse deflecting stream to control the relative alignment between the impacting streams. The change in relative momentum or strength results in a change in the impact position relative to the output orifice means and a related change in the output. As more fully disclosed in the above patents, the impact modulator provides a highly sensitive high gain fluidic device. In addition to the desirable high signal gain, the impact modulator also provides a high input signal impedance and a low output signal impedance while essentially isolating the output and input signals. The device, therefore, is peculiarly adapted to perform amplifying and switching functions similar to electronic devices. Although the impact modulator has been found to provide an unusually satisfactory fluidic device, a substantial number of such devices and related fluidic devices have generally been provided in a complete control system.

The present invention is particularly directed to a highly versatile fluidic device having a plurality of inputs which permit, by proper selection of inputs, creation of either positive or negative amplification as well as various switching functions corresponding to various logic functions such as the AND, NOR, and OR functions as well as many other logic functions employed in control systems.

In accordance with the present invention, a main jet or stream is established within a reference chamber, and providing a selected output in a receiving means in the absence of any control signals acting on said stream. A plurality of cascaded control signal stream forming means are mounted to establish direct inter-acting control streams terminating in a controlled primary control signal stream which engages said main stream with a perpendicular control component to thereby control the effective strength of said stream at the receiving means. The cascaded control stream forming signal means permit changing of the set point of the system without changing the main supply as well as permitting both negative and positive gain of the output. Further, by providing a plurality of cascaded control stream systems, the fluidic device may be used with selected gain characteristics and may be used to perform a substantial number of different logic functions. More particularly, the present invention includes a first primary control stream forming means which projects a primary control stream at an angle to the main stream and impinges on the main stream with a perpendicular control component. The primary control stream may advantageously, applicants have found, include a momentum component opposed to that of the main jet or stream. Although the signal stream does not establish an impact position in the sense of the teachings of the Bjornsen et al. patents, the angular location does not appear to improve the fluidic action. In accordance with the present invention, a modifying or secondary control stream forming means is mounted to the one side of the primary control stream path and is adapted to establish a secondary control stream which will impinge on and deflect the first control signal stream. In operation, providing an input signal to the first stream forming means reduces the effective strength of the main stream with respect to the output or receiving means and provides a negative gain control of a given characteristic. In accordance with the present invention, provision of a signal at the secondary stream forming means effectively removes the power of the first control stream and results in an opposite gain characteristic. The device of this invention provides particularly satisfactory and versatile operation when incorporated in a fluidic device of the impact modulator construction because of the very high gain characteristic of such devices. This establishes a very convenient and accurate controllable switching means for establishing logic functions.

In accordance with a particularly novel aspect of the present invention for establishing pure fluid logic control switching, the first and second control stream forming means are provided as described above. In addition, a pair of similar third and fourth cascaded control stream forming means are provided to engage some other portion of the power or main stream. The primary control signal means, either separately or simultaneously, may create momentum interchange which effectively reduces the output pressure to a turn-off or cut-off level and thus provide a pure fluid NOR function. The same device will provide an AND function by establishing a selected set pressure at the primary control signal stream forming means. In the absence of a signal at either of the secondary means, the output pressure turns-off in accordance with the fixed bias pressures similar to the NOR element function. If a signal is now applied to either one, but only one of the secondary stream forming means, the momentum interaction will occur at the one related pair with removal of the primary control signal stream. The set strength of the complementing primary control signal stream maintains the cut-off state. However, if signals. are simultaneously applied to both of the secondary stream forming means, momentum interactions simultaneously diminish both primary signal streams such that an output pressure is regained. In this mode, the device therefore functions as a two input AND gate.

The device can be readily extended by providing additional stream forming means radially and/or axially oriented about the power stream. The various cascaded stream forming means may be angularly oriented with respect to the controlled stream in accordance with the teaching of this invention to establish a velocity or directional component of the control signal stream opposed to the signal or the path of the controlled stream. However, the streams require a perpendicular component and may even be angularly oriented to establish a component aiding the controlled stream within the broadest aspects of this invention.

Applicants have found that the present invention provides an exceptionally versatile element which readily performs the various functions required in fluid control systems including positive amplification, negative amplification as well as logic switching. When employed with the concept of the impacting modulator, this multiple function control by a single fiuidic element retains all of the advantages related with the impact modulator including; extremely high signal gain; high input signal impedance; low output impedance and essentially complete isolation between output and input signals.

The drawing furnished herewith illustrates the best mode presently contemplated by the inventors for carrying out the subject invention and clearly discloses the above advantages and features as well as others which will be readily understood from the following description.

In the drawings:

FIG. 1 is a pictorial view of an impact modulating fiuidic device constructed in accordance with the present invention;

FIG. 2 is a vertical longitudinal section of the fluidic device shown in FIG. 1;

FIG. 3 is a vertical transverse section taken generally on line 3-3 of FIG. 2;

FIG. 4 is a graphical illustration of the amplifying characteristics obtainable with the fluidic device shown in FIGS. l3;

FIG. 5 is a view similar to FIG. 3 illustrating the operation of the fiuidic device in the positive gain region of the fiuidic device;

FIG. 6 is a schematic illustration of the equivalent logic circuitry produced by the multiple input fluidic device shown in FIGS. 1 through 3; and

FIG. 7 is a view similar to FIG. 2 illustrating a modification to the structure.

Referring to the drawings and particularly to FIGS. 1 and 2 the present invention is shown employing the basic teaching of the Bjornsen et al. Pat. 3,272,215. The fluidic element includes a pair of opposed main power stream nozzles, 1 and 2 which are mounted preferably in opposed aligned relationship and establish opposing impacting streams 3 and 3 within a reference environment chamber 5. In the illustrated embodiment of the invention, the main nozzle 1 is selected as the independent power stream nozzle, and the nozzle 2 is the dependent nozzle. A control or output orifice element 6 is mounted adjacent the dependent nozzle 2 and in the three dimensional device shown, defines an encircling output chamber 7 between the dependent nozzle 2 and the control orifice element 6. The orifice element 6 includes the control aperture or orifice 8 aligned with the path of streams 3 and 4. The

main power streams 3 and 4 impact at a position 9 related to the relative strength of the opposing impinging streams 3 and 4. Generally, the impact position 9 is at or adjacent the orifice 8 in accordance with the teaching of the Bjornsen et al. patent with the output level dependent upon the relative position therebetween. In the illustrated embodiment of the invention, a fluid load 10 is diagrammatically shown connected to the output chamber 7.

The streams 3 and 4 are thus established with predetermined strength to locate the impact position 9 with respect to the control orifice 8 to establish a predetermined pressure or flow signal to the load 10. In accordance with the present invention, as shown in the drawing, a pair of primary signal stream forming nozzles 11 and 12 are provided generally to the opposite sides of the stream 3 emitted from the independent nozzle 1. The nozzles 11 and 12 terminate in corresponding stream forming apertures 13 and, in the illustrated embodiment of FIGS. 13, the axis of the nozzles each defining an included angle 14 with respect to the axis of the power stream 3. The angular orientation of the nozzles 11 and 12 establish similar primary control signal streams 16 and 17, each having a component perpendicular to the main line or stream path of the power or controlled stream 3 and an opposed component.

As most clearly shown in FIGS. 3 and 5, applicants have found that the nozzles 11 and 12 are preferably positioned with the axis of the related streams 16 and 17 oppositely offset with respect to the axis of the main stream 3.

Referring particularly to FIG. 4, a graphical analysis is illustrated of the output pressure versus the input signal pressure for the operation of the device. For example, if the primary signal nozzle 11 is cut off and a signal is applied to the primary signal nozzle 12, the output pressure at chamber 7 will generally correspond to the negative gain line 18 shown in FIG. 4. A similar result is established by cutting off nozzle 12 and applying a signal to nozzle 11. Furthermore, signals at both nozzles 11 and 12, due to the angular orientation, will result in the negative gain characteristic. Thus, in the absence of a signal at either of the nozzles 11 and 12, a maximum output pressure appears in the chamber 7 which is controlled by the pressure of the independent power stream 3 and the dependent power stream 4. As an increasing pressure is applied to the signal nozzles 11 or 12, the corresponding control stream 16 or 17, either alone or together, reduces the momentum strength of the independent primary stream 3 resulting in an outward movement in the impact position 9 with respect to the orifice 8. This will result in a reduced output until the cut-off point 19 is established.

In accordance with the present invention, secondary signal stream forming nozzles 20 and 21 are disposed to the opposite sides of the independent stream 3 and particularly located to control the primary signal control streams 16 and 17, respectively. The control streams 22 and 23 respectively interengage and control the strength of the control streams 16 and 17.

As the nozzles 20 and 21 are similarly positioned in the illustrated embodiment of the invention, the nozzle 20 is hereinafter described with that of the nozzle 21 similarly identified by corresponding primed numbers.

Thus, the nozzle 20 is located with its aperture directed toward the related primary control signal stream 16 such that the stream 22 includes a momentum component which is perpendicular to stream 16. In the illustrated embodiment, the nozzle 20 is angularly oriented to define an inclusive angle 24 between the axis of nozzles 20 and 11, and therefore the related stream paths, which is greater than degrees such that stream 22 includes a vector force or momentum opposing the control stream 16. Stream 22 is primarily, however, a deflection control which positions the primary signal stream 16 diametrically or laterally of the primary stream 3. Thus, in the absence of a signal at nozzle 20, the primary control signal stream 16 is directed into engagement with the primary stream 3 and at a strength solely dependent upon the pressure of the related signal nozzle 11. The application of a pressure to the nozzle 20 forms control stream 22 which engages the stream 16 and causes it to deflect laterally of the stream 3 in accordance with the strength of the control stream 22. The latter, of course, is directly controlled by the pressure and flow of the nozzle 20. Thus. as the control stream 16 deflects laterally of the main stream 3 under the action of stream 22, the strength of the latter increases relative to the opposed stream 4. As a result, the impact position 9 moves in the direction of the orifice 8 with a corresponding increased pressure in the output chamber '7. This results in a positive gain characteristic, shown by the line 25 in FIG. 4. The gain characteristic is that shown obtainable with an impact modulator such as shown in the preferred construction of the present invention.

The application of a control signal to the nozzle 21 similarly establishes control stream 23 which in turn controls the control stream 17 with a corresponding positive gain characteristic.

Applicants have found that the cascaded control signals applied to a controlled stream in a fluidic device is a very significant feature in the design and construction of fluidic controls. The cascaded signal streams allow convenient set point adjustment by adjusting the fixed or set pressure of primary control signal stream while maintaining the same main stream. This is in contrast to the usual requirement of adjusting the main supply and then providing coordinated adjustment of the input and output circuits.

The very large, positive gain obtainable with the present invention particularly adapts the illustrated embodiment of the invention to a multiple input logic control unit.

A logic NOR and an AND function is demonstrated by the following truth tables.

Referring particularly to the NOR function table, the device provides a two input NOR functions by employing pressure signals at the primary signal control nozzles 11 and 12; without control signals at the secondary control signal nozzles 20 and 21. With the supply pressure to both the independent nozzle 1 and the dependent nozzle 2, the given impact position 9 is established. Application of a signal pressure to either or both of the control signal nozzles 11 and 12 establish a momentum interaction with the independent primary stream 3 which reduce its relative strength to cutoff. Thus, in the truth table, a binary indicates absence of pressure and a binary 1 indicates a selected set pressure sufficient to move the output to cutoff on the negative gain curve 18.

The device can be extended to receive a greater number of inputs by providing additional input nozzles or apertures, not shown, similarly oriented toward the independent nozzle axis to provide similar interaction with the independent primary stream 3.

Referring to Table 2, the AND function is similarly accomplished by employing all 4 signal inputs. Thus, the signal pressures are suplied to the primary signal control nozzles 11 and 12 with a predetermined fixed bias level sufiicient to hold the output at cutoff.

If a signal is applied to either of the nozzles 20 or 21, there is a momentum interaction between the related control streams. For example, if a signal is applied to the secondary control nozzle 20, the related stream 22 causes a related deflection of the control stream 16. This results effectively in a reducing or diminishing of the corresponding input signal. However, the output pressure at chamber 7 is held in the cutoff position by the fixed bias pressure signal stream 17 of the oppositely disposed primary control signal nozzle 12. Similarly, if a signal is only applied to the nozzle 21 but not to nozzle 20, a similar result will follow. However, if signals are simultaneously applied to both of the secondary control nozzles 2t) and 21, to simultaneously establish the related control streams 22 and 23, there is the momentum interchange with the several control signal streams 16 and 17 to both sides of the primary stream 3. The momentum interaction diminishes the strengths of both primary control streams 16 and 17 such that the output pressure is regained and the AND gate is turned on. Thus, in the illustrated embodiment of the invention, the device functions as a two input AND gate in accordance with the truth functions as set forth in Table 2.

As with the NOR function, the illustrated device can be readily extended to a multiple AND gate by inserting additional pairs of control signal means.

The versatility of the present device and the reduction in systems components compared with the NOR logic is illustrated by the schematic fiuidic circuit 26, shown in FIG. 6. The corresponding input elements or nozzles are diagrammatically shown as the circular inputs with corresponding numbering for clarity and simplicity of explanation. The single integrated four input device provides the equivalent of five individual logic elements including a pair of single input inverter logic units 27 and 28 interconnected to the primary signal control nozzles 11 and 12 and three dual input inverter logic units 29, 3t and 31 connected to nozzles 20 and 21 and functionally to units 27 and 28. The logic inverter unit 29 has its dual inputs connected respectively to the output of the logic unit 27 connected with nozzle 11 and the related secondary signal nozzle 20. The second dual input logic inverter unit 30 is similarly connected to the logic inverter unit 28 associated with nozzle 12 and with the related secondary nozzle 21. The final logic inverter unit 31 has its dual inputs connected to the outputs of units 29 and 30 and produces the output signal at chamber 7. The illustration of the equivalent circuit of FIG. 7 also clearly indicates other logic functions which can be obtained by proper inputs as Well as various analog functions. For example, the inhibited OR, inhibited NOR, and a set-reset flip-flop.

The magnitude of the gain particularly in the positive gain region is highly dependent upon the inclusive angle between the signal stream forming means and the controlled stream. As the angle increases, the eifect of the signal pressure or flow of the secondary signal stream forming means increases With a resulting higher gain. Thus, the fluidic device may be constructed with pluralities of input apertures with different inclusive angles to permit different gain values or by suitable construction the means could even be provided with an adjustable angular setting for varying of the gain values of any given pair of signal stream forming means. This would thus provide a multiple gain amplifier with a continuously adjustable or discreet gain values depending upon the setting of the stream forming means. Similarly, the axial position of the cascaded streams with respect to the main stream varies the gain of the control stream.

In FIG. 7, a proposed modification to the system of FIG. 2 is shown. Elements in the embodiment of FIG. 7 are identified by primed numbers taken from. FIG. 2.

In FIG. 7, the primary control nozzle 12 and the related secondary control nozzle 21' are shifted axially outwardly from nozzle 1. The gain of the first cascaded gain 11' and 20' will therefore be greater than the gain of the second cascaded gain 12' and 20.

The illustrated four input device can be readily expanded by the addition of other pairs of input stream forming means operating on the primary control signal streams and/or other control signal streams. Although the teaching of this invention can be applied to any fluidic device, the incorporation as a part of an impact modulator is particularly advantageous in view of the highly desirable characteristics of such devices as heretofore discussed and more fully discussed in the Bjornsen et al. patent.

In the above embodiment of the invention, the paired, cascaded control means are mounted on generally diametrically opposite sides of the main controlled stream. Further, the controlling streams are angularly oriented to including a momentum component opposed to that of the controlled stream. Although, for the purposes and functions described, the above system has been found to produce highly satisfactory results, the member and particular arrangement of the cascaded control signal streams may be modified as desired. For example, the controlling stream may be positioned perpendicular to the controlled stream, or to include an aiding as Well as a perpendicular component. Although a pair of cascaded signal streams are shown, the number may be extended as desired.

The present invention thus provides a single device which can function in accordance with a substantial number of different manners in accordance with the selected inputs, providing positive gain, negative gain and/ or logic switching functions.

We claim:

1. A fluidic device, comprising a main stream forming means for establishing a main stream, a first primary control stream forming means disposed to one side of the path of the main stream, said first primary control stream forming means being agular oriented with respect to the main stream forming means and establishing a primary control stream aligned with and engaging said main stream, with a momentum vector opposing said main stream and a secondary control stream forming means disposed to the same side of the main stream in alignment with said first control stream path and establishing a secondary control stream controlling the effective strength of said first control signal stream and thereby the effective strength of the main stream.

2. The fluidic device of claim 1 wherein said secondary control stream forming means is angularly oriented with respect to said primary control signal stream means and establishing a secondary control stream having a momentum vector opposing said primary control stream.

3. The fluidic device of claim 1, having a second main stream forming means establishing a second main stream opposing said first main stream and defining an impact position, and means to sense the impact position.

4. The fluidic device of claim 1, having a second main stream forming means aligned with the first meain stream means and establishing an opposed main stream impacting with the first main stream and defining an impact position and forming a part of an output means for detecting the impact position, a second primary control stream forming means mounted in spaced and angularly oriented relation to the first primary control stream forming means and establishing a corresponding second primary control stream, and a second secondary control stream forming means mounted and oriented With respect to the second primary control stream in accordance with the first secondary control stream forming means relative to the first primary control stream.

5. The fluidic device of claim 4, wherein said first and second secondary control stream forming means have output orifice means oriented to establish streams having a component direction opposed to the corresponding first and second primary control streams.

6. A fluidic device, comprising a main stream forming same side of the main stream in alignment with said first control stream path and establishing a secondary control stream controlling the effective strength of said first control signal stream and thereby the etfective strength of the main stream, a second main stream forming means aligned with the first main stream means and establishing an opposed main stream impacting with the first main stream and defining an impact position and forming a part of an output means for detecting the impact position, a second primary control stream forming means mounted in axially spaced relation to the first primary control stream forming means and establishing a second primary control stream, and a second secondary control stream forming means mounted and oriented with respect to the second primary control stream to control the eflec tive strength of the second control signal stream.

7. A fluidic device, comprising a main stream forming means for establishing a main stream, a first primary control stream forming means disposed to one side of the path of the main stream and establishing a primary control stream aligned with and engaging said main stream, a secondary control stream forming means disposed to the same side of the main stream in alignment With said first control stream path and establishing a secondary control stream controlling the effective strength of said first control signal stream and thereby the effective strength of the main stream, a second main stream forming means aligned with the first main stream means and establishing a second main stream impacting With the first main stream and defining an impact position, an output orifice means mounted adjacent the impact position and forming a part of an output means for detecting the impact position, a second primary control stream forming means mounted to the opposite side of the first main stream path and generally oriented in accordance With the first primary control stream means and establishing a corresponding second primary control stream, and a second secondary control stream forming means mounted to said opposite side and oriented with respect tot he second primary control stream in accordance with the first secondary control stream means relative to the first primary control signal stream, said first and second primary control streams having output orifice means oriented to establish streams having a component direction opposed to said first main stream, and said first and second secondary control stream means having output orifice means oriented to establish streams having a component direction opposed to the corresponding first and second primary control streams.

8. A fluidic device, comprising a main stream forming means to establish a main stream, a first plurality of primary control stream forming means spaced about the path of the main stream angularly oriented with respect to the main stream and each establishing a primary control stream aligned with said main stream and a plurality of secondary control signal stream means aligned with a corresponding primary control stream path and each establishing a secondary control stream aligned with and deflecting the corresponding stream laterally of the main stream.

9. The fluidic device of claim 8 having said primary control stream forming means axially spaced about the path of the main stream.

10. The fluidic device of claim 8 having said primary control stream forming means circumferentially spaced about said main stream.

11. A fluidic device, comprising a main stream forming means to establish a main stream, a first plurality of primary control stream forming means spaced about the path of the main stream and each establishing a primary control stream aligned with said main stream, and a,

9 plurality of secondary control signal stream means aligned with a corresponding primary control stream path and each establishing a secondary control stream aligned with and deflecting the corresponding stream laterally of the main stream, said primary control stream forming means define a stream with the axis of the stream being offset of the axis of the main stream.

12. A fluidic device comprising a main stream forming means for establishing a main stream along a selected path, a plurality of control stream forming means circumferentially spaced about the main stream path, and each establishing a control signal stream engaging the side of the main stream, each of said control stream forming means defining an inclusive angle with the main stream forming means in excess of ninety degrees to establish a signal stream having momentum vector opposing the momentum of the main stream along said path.

13. The fluidic device of claim 12 having a pair of said control stream forming means similarly disposed to opposite sides of said main stream with the path of the related control streams offset to the opposite sides of the axis of said main stream.

14. The fluidic device of claim 12 having a plurality of secondary control stream forming means located to establish secondary control streams aligned with the streams of a plurality of said first named control stream forming means.

15. A fiuidic device, comprising a main stream forming means for establishing a main stream, a first plurality of cascaded control stream forming means establishing a primary control stream engaging said main stream and controlling the effective strength of said main stream, a second plurality of cascaded control stream forming means circumferentially spaced from the first plurality to the diametrically opposite side of the main stream and providing a generally corresponding intersection with said main stream signal means selectively connected to said control stream forming means to effectively out 011 said main stream With selected corresponding signals at either or both control stream forming means.

16. The fiuidic device of claim 15 wherein said first and second control stream forming means have the axis of the related control streams intersecting said main stream to the opposite sides of the axis of said main stream.

References Cited UNITED STATES PATENTS 3,170,476 2/1965 Reilly 137-815 3,186,422 6/1965 Boothe 13781.5 3,272,215 9/1966 Bjornsen et a1 137-815 3,455,317 7/1969 Smith 1378l.5

FOREIGN PATENTS 1,347,426 11/1963 France 137-815 WILLIAM R. CLINE, Primary Examiner 

